Box latch



Sept. 1,1970

W. T ROTTER BOX LATCH 2 Sheets-Sheet 1 Filed July 26, 1967 NN 7/////Vv///////W-f//// m ww mw N WALTER Www/'TER ATTORNEYS W. TROTTER sept. 1,1970 BOX LATCH 2 Sheets-Sheet 2 Filed July 26, 1967 N\ Ow Q d`.\ \Aw mwn @m Sv, OW.. x1 I wml ON\ N mm.

l I l l l l l l Nw MV1 mm INVENTOR. WHL TER TRO 1- TE R 5 HTTGRNEYSUnited States Patent O 3,526,422 BOX LATCH Walter Trotter, Fair Lawn,NJ., assignor, by mesne assignments, to Rex Chainbelt Inc., Milwaukee,Wis., a corporation of New York Filed July 26, 1967, SerrNo. 656,276Int. Cl. Ec 19/14 U.S. Cl. 292-113 1 Claim ABSTRACT OF THE DISCLOSURE Animproved box latch in which a limited lost motion toggle linkage mountsa handle on one of two members to be joined for movement between aclosed position at which it houses the toggle mechanism and an openposition. One form of the toggle linkage incorporates resilient meansfor urging the parts toward one limit of the lost motion. Another formof the toggle linkage incorporates means for adjusting the amount oflost ymotion provided. The assembly may be provided 'with auxiliaryreleasable means for holding the latch in either of its open or closedpositions.

BACKGROUND OF THE INVENTION There are known in the prior art latches forsecuring a box lid -to the box bottom, for example. One type of latchincludes a handle on one of the members which pivotally supports adrawbar for movement between a position at which it is out of engagementwith a strike on the other of the members and a position at which thedrawbar engages the strike. This type of latch may incorporate a beyonddead center or toggle action for holding the parts together.

Latches of the type described above incorporate a number ofdisadvantages. First, a relatively high degree of care must be exercisedin mounting the latch assembly and the strike on the respective membersto be joined in order that the latch will operate effectively.

Very often boxes or the like on which the latch assemblies are mountedare to be painted after the assembly has been placed on the box. Inconstructions of the prior art when this operation is performed, caremust be taken to avoid painting the operating parts of the latchassembly.

Another disadvantage of latches of the type described above known in theprior art is that the latch assembly falls open when not engaged withthe strike so that if mounted vertically, it may ilop across the partingline of the structure to which it is attached and thus interfere withclosing of the structure and, possibly, 'be damaged.

I have invented an improved box latch assembly which overcomes thedefects of latches of the prior art such as are adapted to secure a boxlid on a box bottom, for example. My latch is so constructed that it isreleasably held in the closed position even when the latch element isout of engagement with the strike. My assembly thus facilitates paintingof a container or the like after the latch assembly has been mountedthereon. My latch assembly is releasably held in the open positionthereof so that it cannot fall or op out of that position. My latchassembly is easily installed in that minor inaccuracies in installationwill not affect its operation.

SUMMARY OF THE INVENTION One object of my invention is to provide animproved box latch, the operation of which is not seriously affected byinaccuracies in installation.

Another object of my invention is to provide an improved box latch whichfacilitates painting of the handle without affecting the operatingparts.

A further object of myv invention is to provide an improved box latchwhich will not fall or flop from its open position even if verticallymounted.

Another object of my invention is to provide an irnproved box latchwhich is relatively inexpensive to construct.

Other and further objects of my invention will appear from the followingdescription.

In general my invention contemplates theprovision of an improved boxlatch in which a limited lost motion toggle linkage connects a latchhandle to a bracket on one of the members to be joined for movementbetween a closed position in which the handle houses the linkage and inwhich the handle is adapted to engage a strike on the other member andan open position of the handle. I so construct my latch that the handleis releasably held in its open position and is releasably held in itsclosed position though out of engagement with the strike. I may providemy latch with resilient means for urging the lost motion linkage to onelimit of its movement and I may provide my latch with means foradjusting the extent of the lost motion.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings whichform part of the instant speciiication and which are to be read inconjunction therewith and in which like reference numerals are -used toindicate like parts in the various views:

FIG. 1 is a side elevation of one form of my improved box latch with apart broken away.

FIG. 2 is a sectional view of the form of my improved box latch shown inFIG. 1, taken along the line 2-2 of FIG. l.

FIG. 3 is a sectional view of the form of my improved box latch shown inFIG. l, taken along the line 3 3 of FIG. 1.

FIG. 4 is a side elevation of a further form of my improved box latchwith a part lbroken away.

FIG. 5 is a fragmentary side elevation of another form of my improvedbox latch with a part broken away.

FIG. 6 is a fragmentary side elevation of yet another form of myimproved box latch with a part broken away.

FIG. 7 is a sectional view of the form of my improved box latch shown inFIG. 6 taken along the line 7-7 thereof.

DESCRIPTION OF THE -PREFERRED EMBODIMENTS Referring now to FIGS. 1 to 3of the drawings, my improved -box latch indicated generally by thereference character 10 is adapted to join a first member 12 which may,for example, be a box bottom and a second member 14 which may be a boxlid. I employ any suitable means such, for example, as rivets 16 or thelike to secure a mounting bracket 18 having sides 20 and 22 to themember 12. A pivot pin 24 supported in the sides 20 and 22 pivotallysupports a spring cartridge indicated generally by the referencecharacter 26. The cartridge 26 includes a casing 28 readily formed fromsheet metal so as to have sides 30 and 32, through which the pin 24extends, and a bottom 34. I form slots 36 in each of the sides 30 and 32adjacent the end of the cartridge casing 28 remote the pivot pin 24.

The assembly 10 includes a handle 38 having sides 40 and 42 whichreceive a'handle pivot pin 44. The handle 38, like the cartridge casingand the supporting bracket, may readily be formed from any suitablesheet metal such, for example, as sheet steel. I form the handle withside recesses 46 and `48 for receiving heads 50 on the ends of thehandle pivot pin 44. Handle 38 has a forward end wall 52 carrying alatch element 54 adapted to engage a strike to be described hereinafter.The handle pivot 44 extends through the openings 36 in the cartridgesides 30` and 32. A plurality of coil springs 56 extending along thelength of the cartridge case bear between the pivot pin 24 and the pivotpin 44 normally to urge handle 38 to the left as viewed in FIG. l.

Any suitable means such, for example, as rivets 8 secure a strike 60' tothe other member 14 of the two members to be joined. I provide thestrike 60' with a recess 62 for receiving the latch nose 54 of thehandle 38.

One or more leaf springs y64 carried by the rivets 16 engage theunderside of the cartridge 26. From the structure thus far described, itwill be seen that in the positions of the parts illustrated in FIG. 1,springs 56 normally urge pivot pin 44 and the handle 38 to the left todraw the front end wall 52 of the handle into engagement with the strike60. Moreover, in the position of the parts shown, pin 44 is in a beyonddead center position with respect to pin 24. To move the handle latch 38out of engagement with the strike 60, an extension 66 on the handle isgrasped and the handle is moved in the direction of the arrow in FIG. l.When that occurs, the handle pivots about a point to the right of pin 24as viewed in FIG. 1 to move pin 44 upwardly. As the pin moves upwardly,it moves slightly to the right along the slots 36 against the action ofthe springs 56. Ultimately, the pin 44 moves upwardly past a dead centerposition with respect to pin 24 and wall 52 can vbe moved out ofengagement with the strike 60 to permit handle 38 to be moved in acounterclockwise direction around its pivot `44 to the dot-dash lineposition shown in FIG. 1. In that position of the parts, springs 64engage the lower righthand corner of the cartridge casing 2-8 to holdthe handle latch 38 in its fully open position.

If now with part 14 remote part 12 the handle latch 38 is moved from itsopen position back to a position close to that illustrated in full linesin FIG. 1, and with the handle 38 housing the operating parts, thehandle will releasably be held in that position by the action of thesprings 64 on the cartridge casing 28. It will further be appreciatedthat in this relative position of the parts, handle latch 38 completelyhouses the operating mechanism so that paint or another suitable linishcan be applied to the member 12 and to the handle or to the outersurface of the handle without contaminating the operating parts. It willbe appreciated that the pin 24 and the pin 44 riding in the slots 36forms a lost motion togglelinkage between the handle latch 38 and thebracket 18. I so construct the slots 36 as to provide a positivemetal-to-metal stop when pin 44 moves far enough to the right to engagethe righthand edges of openings 36 before the springs 56 are excessivelycompressed.

Referring now to FIG. 4, I have shown an alternate form of my improvedbox latch in which an elongated leaf spring 68 replaces the leaf springs`64. In that form of my latch I provide a retaining flange 70 on the endof extension 66 so that the spring 68, which extends from the flange 70to the end wall 52 of the handle latch 38, is retained within the latch.Spring 68 is so shaped that a portion thereof bears on the top of thecartridge casing 28 to hold the casing in the position it occupies inboth the closed and the open positions of the handle latch 38. Thus, itachieves the same functions as those which are performed by the springs64 in the form of the invention shown in FIG. 1.

Referring now to FIG. 5, in a still further form of my improved 'boxlatch, I provide the cartridge casing with a -pin 72 having a squareshank 74 against which the springs 56 bear. In this form of the device,the sides of the square shank tend to hold the handle latch 38 in thepositions to which it has been moved in a manner similar to that inwhich the springs 68 or 64 function. It will be appreciated that pin 72is fixed in the sides 20 and 22 of bracket 18 and that the casing 28rotates on the pin 72.

Referring now to FIGS. 6 and 7, I have shown yet another form of myinvention in which I provide means for effectively adjusting the lengthsof the slots 36, thus to limit the lost motion provided. In this form ofmy invention a knurled nut 76 is carried by the shank 7'8 of a T- bolthaving a T-head 80' adjacent the handle pin 44. Nut 76 extends throughopenings 82 and 84 in the top and in the bottom of the casing 28 so asto be accessible to permit it to be turned manually to position theT-head 80 at the desired location along the length of the casing 28.When this form of my latch is moved to its closed or latching position,the pin 44 engages head 80. I provide this form of my latch with twosprings 86 within the cartridge casing 28 at the sides of the T-bolt.The latching action in this form of my latch is provided by theengagement of the head 80 with the pin 44 rather than by the resilientforces exerted by the springs. The springs eliminate any sloppiness fromthe action of this form of my latch.

In operation of the forms of my latch shown in FIGS. l to 5, to join thetwo members 12 and 14 with the handle latch 38 in the open position, itis rotated around its pivot 44 to a position at which the wall 52 isover the strike 60. The handle latch 38 is then moved in acounterclockwise direction, as viewed in the figures, until pin 44 ismoved beyond dead center with respect to the pin 24. In that position ofthe parts, the springs 56 provide a force which draws wall 52 intoengagement with strike 60 to cause the nose 52 to enter slot 62. Whenthe latch is to be released, handle latch 38 is first rotated in aclockwise direction until it has moved suiciently far beyond dead centerin that direction of movement to permit wall 52 to be moved away fromthe strike 60 so that it can be moved to fully open position.

Each of the forms of my latch shown in FIGS. 1 to 5 has means forreleasably holding it in its open position to prevent it from floppingback toward closed position and over the parting line between members 12and 14 if it is, for example, vertically mounted. In FIG. 1 springs 64engage the lower righthand corner of the cartridge 28 to achieve thispurpose. The same function is performed by the spring 68 in the form ofmy latch shown in FIG. 4 and by the square shank 74 in the form of mylatch shown in FIG. 5. Moreover, each of these elements also serves thepurpose of holding the handle latch 38 in its closed position over allof the operating parts, although it is out of engagement with the strike60.

In operation of the form of my latch shown in FIGS. 6 and 7, nut 76 isturned to position the head y80 to provide the desired latching force.As the wall 52 is brought into engagement with the strike 60, engagementof the pin 44 with the head 80l provides the latching action. I may, ofcourse, if desired, provide the form of my latch shown in FIGS. 6 and 7with any of the various means shown in FIGS. 1 to 5 for releasablyholding the latch in its open position and in its closed position.

It will be seen that I have accomplished the objects of my invention. Ihave provided an improved box latch, the operation of which is notaffected by minor inaccuracies in mounting. My box latch can readily bepainted or otherwise nished in its installed condition withoutcontaminating the operating parts thereof. I so construct my latch thatit will not readily flop or fall over the parting line even whenvertically mounted. My improved box latch is relatively inexpensive toconstruct. It is especially adapted for use in installations wherein theavailable space is limited. Its handle is at when the latch is fullyopen.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of myclaim. It is further obvious that various changes may be made in detailswithin the scope of my claim without departing from the spirit of myinvention. It is, therefore, to be understood that my invention is notto be limited to the speciic details shown and described.

Having thus described my invention, what I claim is:

1. A latch assembly including in combination a unitary latch and handlemember comprising sides and a top made up of a web of material extendingbetween said sides substantially from end to end thereof, said sidesextending downwardly from said web, said member having a latch portionat one end of said top and having a manually engageable handle portionat the other end of said top, a bracket, a link, respective pivot pinscarried by said link, one of said pins pivotally supporting said link onsaid bracket, the other of said pins pivotally connecting said handle tosaid link, said link being provided with a longitudinally extending slotfor receiving one of said pins for limited movement along the length ofthe link, a compression spring located between said pins to urge the pinin said slot to one limit of its movement with respect to said link saidhandle being movable from an open position at which said bracket andsaid link are exposed to a closed position at which said latch andhandle member sides and top house said link and said bracket to concealthe same, and an auxiliary spring biased between said link and saidbracket for releasably restraining said member against movement from itsopen position and against movement from its closed position.

References Cited UNITED STATES PATENTS 2,679,417 5/ 1954 Seibert 292-2473,026,133 3/1962 Swanson 292-113 5 3,034,817 5/1962 Willis 292-1133,127,205 3/ 1964 Griiths et al. 292-113 3,162,419 12/ 1964 Blasingame248-361 3,174,784 3/1965 Swanson 292-113 10 3,318,624 5/1967 Poe et al.292-113 2,818,596 1/1958 Martinee 15-317 2,829,912 4/1958 Koch 292-1142,859,996 11/1958 Alkinson 292-114 15 FOREIGN PATENTS 261,245 8/ 1949Switzerland. 971,191 12/ 1958 Germany.

RICHARD E. MOORE, Primary Examiner o R. L. WOLFE, Assistant ExaminerU.S. Cl. X.R. 292-247

